Memory question, why does it creap up throughout day

[slumpey326]

I have done all the tweaks to the Imagio and when I turn the the phone on each morning it starts at 48%. But by the end of the day it could creap up to about 70%. I always close out programs after I use them and I even run htc cleanram a few times throughout the day, yet it wont go back to around 48% unless I do a soft reset. Why is it this.

I thought if you close programs out after using them, the phone wont be using any more memory for the programs.

Please advise.